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authorTejun Heo <tj@kernel.org>2013-03-08 12:43:30 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-08 15:05:34 -0800
commit2e1c9b2867656ff9a469d23e1dfe90cf77ec0c72 (patch)
treeb1f8c8a5fde730b2e3c71239e125e451df039fa5
parent7880639c3e4fde5953ff243ee52204ddc5af641b (diff)
downloadvexpress-lsk-2e1c9b2867656ff9a469d23e1dfe90cf77ec0c72.tar.gz
idr: remove WARN_ON_ONCE() on negative IDs
idr_find(), idr_remove() and idr_replace() used to silently ignore the sign bit and perform lookup with the rest of the bits. The weird behavior has been changed such that negative IDs are treated as invalid. As the behavior change was subtle, WARN_ON_ONCE() was added in the hope of determining who's calling idr functions with negative IDs so that they can be examined for problems. Up until now, all two reported cases are ID number coming directly from userland and getting fed into idr_find() and the warnings seem to cause more problems than being helpful. Drop the WARN_ON_ONCE()s. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: <markus@trippelsdorf.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--lib/idr.c16
1 files changed, 3 insertions, 13 deletions
diff --git a/lib/idr.c b/lib/idr.c
index 73f4d53c02f..00739aaf95a 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -569,8 +569,7 @@ void idr_remove(struct idr *idp, int id)
struct idr_layer *p;
struct idr_layer *to_free;
- /* see comment in idr_find_slowpath() */
- if (WARN_ON_ONCE(id < 0))
+ if (id < 0)
return;
sub_remove(idp, (idp->layers - 1) * IDR_BITS, id);
@@ -667,15 +666,7 @@ void *idr_find_slowpath(struct idr *idp, int id)
int n;
struct idr_layer *p;
- /*
- * If @id is negative, idr_find() used to ignore the sign bit and
- * performed lookup with the rest of bits, which is weird and can
- * lead to very obscure bugs. We're now returning NULL for all
- * negative IDs but just in case somebody was depending on the sign
- * bit being ignored, let's trigger WARN_ON_ONCE() so that they can
- * be detected and fixed. WARN_ON_ONCE() can later be removed.
- */
- if (WARN_ON_ONCE(id < 0))
+ if (id < 0)
return NULL;
p = rcu_dereference_raw(idp->top);
@@ -824,8 +815,7 @@ void *idr_replace(struct idr *idp, void *ptr, int id)
int n;
struct idr_layer *p, *old_p;
- /* see comment in idr_find_slowpath() */
- if (WARN_ON_ONCE(id < 0))
+ if (id < 0)
return ERR_PTR(-EINVAL);
p = idp->top;